Prevalence of the metabolic syndrome in African populations: A systematic review and meta-analysis.

BACKGROUND: The metabolic syndrome (MS) is a leading cause of death worldwide. Several studies have found MS to be prevalent in various African regions. However, no specific estimates of MS prevalence in African populations exist. The aim of this study was to estimate the overall prevalence of MS in the African populations. METHODS: A systematic review was conducted in PubMed, Web of Science, Africa Index Medicus, and African Journal Online Scopus to find studies published up to the 15th of August 2022. Pooled prevalence was calculated based on six diagnostic methods. The pooled prevalence of MS was estimated using a random-effects model. Our risk of bias analysis was based on the Hoy et al. tool. A Heterogeneity (I2) assessment was performed, as well as an Egger test for publication bias. PROSPERO number CRD42021275176 was assigned to this study. RESULTS: In total, 297 studies corresponding to 345 prevalence data from 29 African countries and involving 156 464 participants were included. The overall prevalence of MS in Africa was 32.4% (95% CI: 30.2-34.7) with significant heterogeneity (I2 = 98.9%; P<0.001). We obtained prevalence rates of 44.8% (95% CI: 24.8-65.7), 39.7% (95% CI: 31.7-48.1), 33.1% (95% CI: 28.5-37.8), 31.6% (95% CI: 27.8-35.6) and 29.3% (95% CI: 25.7-33) using the WHO, revised NCEP-ATP III, JIS, NCEP/ATP III and IDF definition criteria, respectively. The prevalence of MS was significantly higher in adults >18 years with 33.1% (95%CI: 30.8-35.5) compared to children <18 years with 13.3% (95%CI: 7.3-20.6) (P<0.001). MS prevalence was significantly higher in females with 36.9% (95%CI: 33.2-40.7) compared to males with 26.7% (95%CI: 23.1-30.5) (P<0.001). The prevalence of MS was highest among Type 2 diabetes patients with 66.9% (95%CI: 60.3-73.1), followed by patients with coronary artery disease with 55.2% (95%CI: 50.8-59.6) and cardiovascular diseases with 48.3% (95%CI: 33.5-63.3) (P<0.001). With 33.6% (95% CI: 28.3-39.1), the southern African region was the most affected, followed by upper-middle income economies with 35% (95% CI: 29.5-40.6). CONCLUSION: This study, regardless of the definition used, reveals a high prevalence of MS in Africa, confirming the ongoing epidemiological transition in African countries. Early prevention and treatment strategies are urgently needed to reverse this trend.

Flavonoid-enrich extract of Autranella congolensis (Sapotaceae) protects against aluminium chloride-mediated Alzheimer's disease-like oxidative stress in rat through the antioxidant properties.

Oxidative stress (OS) is well established as a major event in Alzheimer's disease (AD) pathology. One of the mostly-researched classes of antioxidants to manage with overwhelming OS include flavonoids. This study was aimed to investigate the protective effect of A. congolensis extract (HEEAC) on AlCl3-mediated AD-like OS and assess the contribution of its antioxidant flavonoid contents. Female Wistar (250-300 g) rats received orally 50 mg/Kg bw of AlCl3, followed one hour later by doses (150 or 300 mg/kg) of HEEAC or vitamin E at 100 mg/kg daily for eight consecutive weeks. OS related biomarkers were evaluated at the end of treatment. To assess the contribution of flavonoid contents to its activity, HEEAC was fractioned using solvent of varying polarities. Flavonoid-rich extracts obtained were tested for their antioxidant capacity. AlCl3 administration significantly lowered antioxidant enzymes (catalase, glutathione peroxidase) and aconitase levels, reduced total thiol and thiol protein levels and increased lipid peroxidation and protein oxidation levels in brain. When co-administrated with HEEAC at 150 mg/kg, all of these OS related biomarkers were significantly moderated. The efficacity of the extract was significantly higher than vitamin E. Flavonoid-rich fractions extracted mainly n-butanol fraction show strong antioxidant activity, which can be considered as the major antioxidant fraction of this plant. HEEAC protect brain cells against oxidative damage induced by AlCl3, specifically through the strong antioxidant property of its n-butanol flavonoid-rich fraction, which may be a promising agent for preventing oxidative damage in AD.

Clinical characteristics and classification of Cameroonians with obesity and metabolically normal phenotype in the West region of Cameroon.

The objective of this study was to classify and suggest an adequate definition of the metabolically normal phenotype among Cameroonians with obesity in the western Region of Cameroon. A cross-sectional study was conducted in the West Cameroon Region from August 2016 to August 2017. A total of 324 subjects with BMI >27 kg/m2, aged of 20 years and older, and not treated for cardiometabolic diseases were included in the study. Sociodemographic and clinical parameters of the subjects were collected. Four definitions of metabolic status were tested to suggest the definition that best identifies the subjects with obesity but metabolically normal phenotype (MNO) in the study. The prevalence of the MNO phenotype varied from 2.50% to 29.60% according to the definitions used. According to the individual definitions, the prevalence of the MNO phenotype was 29.60% according to Hinnouho, 16.00% according to Mbanya, 7.40% according to Meigs and 2.50% according to Widman. Markers of inflammatory profile (high sensitivity C-reactive protein and tumor necrosis factor-alpha), carbohydrate homeostasis (fasting glucose and homeostasis model assessment), markers of lipid profile (total cholesterol and triglyceride), systolic blood pressure, nitric oxide, adiposity indices (Waist circumference and waist to hip ratio) were significantly lower in MNO subjects for the majority of definitions (p < 0.05). The modified Hinnouho definition showed better specificity (60.90%) and sensitivity (12.10%) for an area under the ROC curve of 0.98. The degree of agreement was low between the different pairs of definition of the MNO phenotype (Kappa< 0.61). There is poor agreement between the different definitions of the MNO phenotype among Cameroonians with obesity. Therefore, the adoption of a universal definition of MNO phenotype should be proposed to facilitate the management of metabolic health in people with obesity.

Effect of aqueous extract of Scorodophloeuszenkeri bark on chronic hyperglycemia and its complications in a diabetic Wistar rat model induced by streptozotocin.

Diabetes and its complications represent a real major public health problem in the world because of its high rates of morbidity and mortality. Chronic hyperglycemia, oxidative stress, dyslipidemia and inflammation play a major role in the pathophysiology of diabetes and its vascular complications. The objective of this study was to evaluate the effect of aqueous extract of S. zenkeri on chronic hyperglycemia and its complications in a streptozotocin-induced diabetic Wistar rat model. The barks of S. zenkeri were washed, dried and crushed; the powder was dissolved in distilled water (1:10 weight/volume) then macerated and the filtrate obtained was dried in an oven. Subsequently, after quantification of the bioactive compounds (total polyphenols, flavonoids and alkaloids) present in the extract, an in vivo study was conducted in an animal model of streptozotocin-induced hyperglycemia. For this fact, the rats were divided into four groups of five rats as folow: a normoglycaemia group (NC), an untreated hyperglycaemia group (PC), two hyperglycaemia groups including a test group receiving by esophageal gavage, the aqueous extract of the bark of S zenkerii (AESZ) at a dose of 300 mg/kg body weight and a control group receiving metformin at a dose of 20 mg/kg body weight. During the treatment which lasted 21 days, the weights have been taken every two days and the blood sugar levels every week. At the end of the treatment, the rats were killed under light chloroform anesthesia; the plasma, hemolysate, serum and liver homogenate prepared were used to assay the biochemical parameters of oxidative stress (catalase, MDA), lipid profile (Triglycerides, total cholesterol and HDL-cholesterol) and immunological (CRP and NFS). It emerged that the extract limited weight loss and caused a reduction in blood sugar of -26.59% after 21 days of treatment; the extract caused an increase in the activity of erythrocyte catalase and a reduction in the concentration of hepatic MDA, as well as a very marked reduction in inflammatory cells and CRP. The extract also caused a reduction in dyslipidemiawhich was materialized by a reduction in CRR, AC, AIP and an increase in CPI. These results suggest that this extract contains bioactive compounds capable of reducing chronic hyperglycemia while preventing its complications, thus justifying its traditional use in the management of diabetes.

Effectiveness of 3 Polyherbal Formulations (EcXaPu, EcXa, and EcPu) on the Management of Oxidative Stress and Hyperglycemia.

Oxidative stress and hyperglycemia are major disorders involved in the occurrence and severity not only of chronic non-communicable diseases but also of infectious pathologies. This study aimed to evaluate the in vitro antioxidant and antihyperglycemic properties of EcXaPu, EcXa, and EcPu. The antioxidant properties were evaluated using 3 mechanisms: radical scavenging; reducing property, and metal chelating. Finally, the antihyperglycemic properties were evaluated by 2 mechanisms: glucose adsorption and cellular glucose capture. The different formulations showed their ability to scavenge DPPH, ABTS, and NO radicals with SC50 ranging from 2.75 to 3.51 mg/ml, from 2.6 to 2.76 mg/ml, and from 2.59 to 3.3 mg/ml, respectively. All the formulations also reduced MoO4 2+ and Fe3+ and chelated Cu2+ and Fe2+. The different formulations adsorbed the glucose with glucose adsorption rates ranging from 72.83% to 87.01%. The different formulations also stimulated cellular glucose uptake, with uptake rates ranging from 31.9% to 50.71% in yeast cells and from 21.81% to 39.45% in muscle cells. These formulations could be potential agents to prevent and/or protect against biological disorders associated with oxidative stress and hyperglycemia.

The neuroprotective effect of Xylopia parviflora against aluminum chloride-induced neurotoxicity in rats.

Neurodegenerative disease such as Alzheimer's disease, are progressive disorders which has been linked to oxidative imbalance and associated perturbations characterised by loss of memory, cognition and cholinergic deficit. To date, cholinesterase inhibition and neuroprotection are the two major strategies in drug development. Xylopia parviflora (Annonacea family) is a spice consumed in Cameroon and has been used in traditional medicine to treat various pains. In this study, X. parviflora was evaluated on behavioural studies, ion homeostasis, cholinesterase inhibitory and antioxidant activities. Rats were exposed to aluminium chloride (75 mg/kg) during 60 days, and were treated with the extract of X. parviflora (150 and 300 mg/kg BW) and two drugs references (Donepezil and Curcumin). Behavioural parameters were assessed using the Morris-Maze test and the Open Field, followed by biochemical investigations, namely, cholinesterase enzyme activity (AChE and BChE), oxidative stress (NO, MDA, GSH level, SOD and Catalase activities) and ion homeostasis (Mg2+ and Ca2+ levels). AlCl3 administration shows a decrease in learning and memory improvement during behavioural studies, significant alteration of the central cholinergic system characterised by an increase in AChE and BChE activities to 2.72 ± 0.002 mol/min/g and 5.74 ± 0.12 mol/min/g respectively, disturbance of ion homeostasis with an increase in Ca2+ level (25.68 ± 3.78 µmol/mg protein) and a decrease in Mg2+ level (15.97 ± 2.05 µmol/mg protein) and an increase in oxidative stress compared to the positive control group. Treatment with the different doses of X. parviflora increased memory and improved locomotion, improved cholinesterase activities, ion homeostasis and stabilized brain oxidative stress levels. The study suggests that X. parviflora could potentially be used for the management of some biochemical alterations associated with Alzheimer's disease. It could even be a good alternative to chemical drugs for neurotoxicity and memory enhancement.

In vitro anticholinesterase potential of some spices consumed in Cameroon and their protective effects on hydrogen peroxide-mediated oxidative stress damage in SK-N-SH cells.

Background: Many neurodegenerative such as Alzheimer's disease (AD) are characterized by cholinergic dysfunction and oxidative stress which is a key event in neuronal death process. Thus, anticholinesterase and anti-oxidation compounds are two promising strategies in the development of AD drugs. Beyond their culinary use, spices are today studies for health purpose. In this study, some spices consumed in Cameroon were evaluated for their anticholinesterase and neuroprotective effects. Methods: Colorimetric methods were used to determine total flavonoid and alkaloid content of a combinated extract (hydroethanolic + ethanolic extracts) of different selected spices. Aftermaths, anti-cholinesterase activity of spice extract was carried out using Ellman's method. Finally, neuroprotective effects performed on human SK-N-SH cells stressed with H2O2 by assessing neuronal survival ( resazurin assay) and neuronal death (LDH assay). Results: Flavonoid content of spices extract were ranged from 22.94 to 32.01 mg EQ/g DM and alkaloid content were ranged from 320 to 896 mg EQu/g DM. Among the spices studied, Xylopia parviflora presented the greatest acetylcholinesterase inhibition with an IC50 = 14 µg/mL. In Cell culture experiments, pre-incubation of SK-N-SH cell with the selected spices at different concentrations were improved neuronal survival and reduced the percentage of neuronal cells dead. Conclusion: The present results reveal that selected spices consumed in Cameroon have good anticholinesterase activity as well as neuroprotective effect on SK-N-SH which may provide new natural compounds that could help in the management of Alzheimer's disease.

Subacute effects of hydroethanolic extracts of the pulp of Gambeya africana on glucose plasmatic levels and oxidative stress markers in diabetic rats.

The management of hyperglycemia and oxidative stress is a key point in the control of diabetes and its complications. The work evaluated the hypoglycemiant and antioxidant properties of pulp extracts of Gambeya africana fruits. The acute toxicity was conducted for 14 days at the dose of 2000 mg/kg via oral gavage. Diabetes was induced in rats by intravenous administration of streptozotocin (50 mg/kg). The effect of the extract on blood glucose levels of diabetic rats was monitored at 2h after administration; and on the 7th and 14th days of treatment (single dose of 400 mg/kg/day). After 2 weeks of treatment, the rats were sacrificed. The oxidative stress markers (Hydroperoxides, Malonedialdehydes, Superoxide Dismutase, Catalase, and Total Antioxidant Capacity) and hepato/nephrotoxicity markers (Alanine Amino Transferase, urea, and creatinine) were determined. The hydroethanolic extract of G. africana fruits has a lethal dose upper than 2000 mg/kg. It significantly decreased glucose levels by 28.29% and 84.86% respectively after 2h and 14th days of treatment. The extract increased the antioxidant status and decrease oxidative stress, especially in the pancreas. This study suggests that the hydroethanolic pulp extract of G. africana fruits is a good hypoglycemiant and antioxidant agent and could be a potential source of compounds for diabetes management.

Lipotropic activities of aqueous extract of Vernonia guineensis Benth. in Wistar rats fed high fat diet.

BACKGROUND: Lipotropic molecules are effective therapeutic targets to counteract non-alcoholic fatty liver disease (NAFLD). Lipotropic compounds are capable of removing fat from the liver and/or manage the reduction of the synthesis or deposition of lipids in the liver. The objective of this study was to evaluate the lipotropic effects of the aqueous extract of leaves of Vernonia guineensis (AEVG) on rats fed high fat diet. METHODS: Twenty male rats with an average mass of 235 g were allow acclimatize for seven days, following which they were divided into four groups of five animals each. The test group was treated with high fat diet (HFD) and AEVG at 400 mg/kgBW, while positive control group received HFD and Fenofibrate at 100 mg/kgBW. The normal control group received a normal diet; and the negative control group received HFD. After 14 days of treatment, animals were sacrificed, blood and organs (liver, heart and kidneys), as well as the faeces were collected for the preparation of plasma and homogenates respectively. Some markers of lipid profil (total cholesterol, triglycerides, HDL-c, LDL-c,) and markers of toxicity (AST, ALT, γ-GT, creatinine) were evaluated. RESULTS: The results obtained showed that a HFD at the hepatic level led to the accumulation of lipids (triglycerides (TG) and total cholesterol (TC)) and had adverse effects on hepatic function by promoting cytolysis. At the plasma level, HFD induced hyperlipidemia. Administration of AEVG at 400 mg/kgBW improved the blood lipid profile and reduced the storage of TG and cholesterol in the liver. AEVG also promoted fecal cholesterol excretion and reduced atherogenic indices which include Total Cholesterol/High-Density Lipoprotein cholesterol (TC/HDL-c) and Low-Density Lipoprotein cholesterol/High-Density Lipoprotein cholesterol (LDL-c/HDL-c). The extract exhibited hepato-protective activity (anticholestasis) and improved glomerular filtration. CONCLUSION: These findings suggest that AEVG possesses lipotropic effects confirming its probable use in the management of non-alcoholic fatty liver disease and its cardiometabolic complications. This virtue could be exploited for local pharmaceutical development.

Effect of Beilschmedia obscura on the prevention of high fat/high sucrose diet induced metabolic syndrome on male Albino Wistar rats.

INTRODUCTION: Beilschmiedia (Lauraceae) is a pantropical genus of about 287 species, distributed in tropical Asia and Africa used in traditional medicines to cure many diseases. This study aimed to explore biological properties of Beilschmiedia obscura (B. obscura) on the prevention and management of metabolic syndrome (MetS) features induced by High Fat/High Sucrose (HF/HS) diet in rats as therapeutic option. METHODS: MetS was induced after administration of HF/HS diet followed by administration of B. Obscura powder at 5% or 10% for 21 days, while the control group received a chow diet and distilled water and the positive control group received the HF/HS diet and distilled water. At the end of the experiment, rats were sacrificed; the parameters of lipid profile, markers of oxidative stress, antioxidant status were evaluated. RESULTS: HF/HS diet successfully induced weight gain, oxidative stress and lipid profile disorders from rats. Treatment with powder of B. obscura at 10% than the 5% showed a reduction of body weight in treated groups and, anti-hyperlipidemic effect by improving lipid profile parameters. Triglycerides, Total cholesterol and LDL cholesterol levels were lower (p<0.05) and HDL-cholesterol levels higher in the treated groups compared to positive control. Inhibition of lipid peroxidation, and improvement protein thiols levels and catalase activity were also observed in treated groups. CONCLUSION: This study revealed that B. obscura whole plant was efficient in reducing biomarkers involved in metabolic syndrome and could efficiently help in its management by preventive effect.

Prevalence and Identification of Serum Markers Associated with Vertical Transmission of Hepatitis B in Pregnant Women in Yaounde, Cameroon.

OBJECTIVE: To determine the prevalence of Hepatitis B Virus (HBV) infection in pregnant women and identify markers associated with vertical transmission of HBV. METHODS: Prospective and cross-sectional study over 10 months on 298 pregnant women attending antenatal clinics in the Cité Verte and Efoulan District hospitals in Cameroon. A dry tube blood collection was performed on all pregnant women and babies born to HBsAg-positive mothers. Serum from the women was used to test for HBsAg through immunochromatography and then confirmed by ELISA. The test for HBeAg, HBeAb and HBcAb and dosage of transaminases were performed on the serum of HBsAg-positive women. Only HBsAg was tested in babies within 24 hours after birth. RESULTS: HBsAg was present in 23 (7.7%) mothers while 275 (92.3%) tested negative. Due to loss to follow-up, we assessed vertical transmission in 20 babies born to20 mothers. In all, eight babies tested HBsAg-positive; six mothers tested positive with HBeAg; 10 mothers with HBeAb and two were simultaneously infected with HBV and HIV. CONCLUSION AND GLOBAL HEALTH IMPLICATIONS: HBeAg and increase in liver transaminases were serum markers associated with the vertical transmission of HBV while HBeAb and anti-HIV therapy were protective markers. There is need to systematically screen all pregnant women for hepatitis B, follow up those that are positive, and administer a dose of gammaglobulin anti-HBs to their children to reduce the risks of chronic hepatitis and hepatocellular carcinoma (CHC) and curb mortality and morbidity due to viral hepatitis B.